Posted
by
samzenpus
on Thursday January 25, 2007 @01:58AM
from the marlon-brando-pocahontas-and-me dept.

eldavojohn writes "The aurora borealis (also known as the Northern Lights) has long been known to be an effect resulting from the Sun's solar wind pushing particles into the earth's magnetic field and atmosphere. In light of the possible danger that these substorms could pose to astronauts & equipment, NASA is now planning a mission to track down these magnetic storms and disturbances. The program's not so catchy name of Time History of Events and Macroscale Interaction during Substorms has a slightly catchier acronym of THEMIS. From the article, "In order to scan the Earth's magnetic field and pinpoint the origin of substorms, THEMIS researchers plan to stagger their spacecraft in different orbits that range in altitude from 10 to 30 times the radius of the Earth (the planet's radius is about 3,962 miles, or 6,378 kilometers).""

Has anyone bothered to fly into the aurora borealis with, like, some sensors strapped to fuselage? Seems kinda like one of the first things you'd try once you had a plane that could fly up to high altitudes.. surely someone has sent weather baloons into the aurora borealis. Of course, it would be piss funny if it turns out that outfitting an X1 era plane with a magnetic field generator and flying it into the aurora borealis gave it some sort of magnetic boost, like riding a wave, and this was fast enough

I think the Earth's field is about 1 gauss, barely enough to move a compass needle, and at that only when the needle is carefully balanced on a good bearing. That is, the forces involved in the aurora are exceedingly weak.

Bah, says you. It's a storm! The reason the sky lights up could be because there's insane amounts of high energy plasma being dragged into the atmosphere. If Startrek DS9 has taught me anything, it is that all women from Trill are hot, and space storms are an inexpensive and improbable source of free propulsion.

The issue that NASA is trying to resolve has much more important value than the previous post is thinking. The mechanisms for the aurora and other processes are very powerful producing electrical currents at the highest levels ever seen. What is more the processes do affect the earth in profound ways. The link between these and the weather is being firmly established. NASA is starting to get the data together that is linking the stellar space behavior and that of all weather on the planet earth.

"The mechanisms for the aurora and other processes are very powerful producing electrical currents at the highest levels ever seen."

You-- and "Thunderbolts"-- want to argue that EM rather than gravity shapes EVEN PLANETARY systems, yet, the aurora borealis is the most powerful electric current observed? The aurora is entirely local to earth!

Hello? The "Thunderbolts" claim that INTERPLANETARY electric arcs shape planets. Surely we would have observed one by now?

"In order to scan the Earth's magnetic field and pinpoint the origin of substorms, THEMIS researchers plan to stagger their spacecraft in different orbits that range in altitude from 10 to 30 times the radius of the Earth (the planet's radius is about 3,962 miles, or 6,378 kilometers)."

Due to what happened with the Mars Polar Lander [wikipedia.org] could we get those figures in just one measurement system, if for no other reason just to avoid possible confusion and the possibility of sending a spacecraft hurtling into the surface of a planet I live on? Thanks.:)

Not just MPL -- I am aware of four different missions that were either destroyed or drastically reduced in functionality (the last one was DART) because a contractor insisted on doing their calculations/modeling/development in imperial units and then flubbed somewhere at a translation to metric at the interface with NASA (twice Lockheed Martin, once OSC, once Boeing).

The abysmal inability of the American Industry to perform a single project in metric units is only one of the reasons why none of them has e

Coordination is good and all, but there's nothing inherently superior about SI units over US customary units. And even if every measurement tool, design program, manufacturing machine and socket set in the US was converted to SI units, you'd still have to deal the conversion, and that conversion would still be susceptible to the sorts of errors you're whining about.Moreover, it's not even as simple as a one-time conversion. There's also the hassle of filling your A/C with what used to be 10.0 lbs of coolant

Hmm...I was brought up using Imperial units. When I learnt metric units, lots of things I was interested in were easier to understand and calculations were simplified.

In one book I read (when I was about 9 years old) it said that a cubic inch of the Sun's core gave of xxx (I don't remember the exact number) horsepower! If they had specified it in metric I could relate it to electric heaters.

Try getting a rough idea of the fraction of a woman's weight her baby is: compare mentally getting the ratio of baby

First, the errors in space flight we were discussing have never been the result of complicated arithmetic, they were the result of mis-applied unit conversion. It's not like space probes come equiped with some guy with a slide rule to do calculations -- the computer is no more likely to mis-calculate 12.685 * 39.553 than 10.000 * 22.934.Second, the only operation that SI units simplify is same-type unit conversion. This is almost never a problem in automation, because unlike people there's no reason to meas

Well, even if something like that did happen, I have the feeling nothing much would come of it down here. Each of THEMIS's probes (there are 5) is about the size of a largish television. Not very big; in fact, plenty small enough to mostly, if not completely, burn up on re-entry.Besides which, they're also pretty light (i.e., low-mass). THEMIS was constructed out of low-magnetic susceptability materials (which, in this case, also happen to be low-mass) so that the probes wouldn't interfere with the local

You just know they think up the name first (THEMIS), then think up words to make a vaguely sciencey phrase to fit it ( Time History of Events and Macroscale Interaction during Substorms ) and then have to sit around wondering what a mission with such a name would actually do. Quite clearly one of the people involved wanted a mission involving time travel but they just ended up with investigating solar wind storms.

I don't know how common this is, but the one time I observed the birth of a new proposal, they made a list of relevant words to facilitate the acronym-finding process. Ideally, you want the acronym to bare some relation to the phenomenon of interest, but that isn't always the case (e.g., ANARChE [Aerosol Nucleation and Real-time Characterization Experiment]). Too bad they couldn't fit hygroscopicity or sulfates in there, since that's what they were really interested in. I've also seen a lot of "acronyms" th

Themis, the goddess of justice, wisdom and good counsel, the guardian of oaths in Greek mythology, represents the THEMIS mission. She will confirm without prejudice, as implied by her fame, one of the two competing theories for auroral eruptions. THEMIS, with her sword (representing instruments) and scales (representing science discoveries), has both power and impartiality.

Basically, the scientists chose this name because they are hoping their mission will help resolve some of

But don't confuse this THEMIS with the Other THEMIS
http://themis.la.asu.edu/ [asu.edu]
NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission
for NASA's Office of Space Science, Washington, D.C. The Thermal Emission
Imaging System (THEMIS) was developed by Arizona State University,
Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing.
The THEMIS investigation is led by Dr. Philip Christensen at Arizona State
University. Lockheed Martin Astronautics, Denver, is the prime contractor
for

In any discussion of the aurora, one might expect that the name Kristian Birkeland might come up. After all, he was the first scientist to ever accurately describe the phenomenon. It's interesting to look back and see why it is that so few people know who Birkeland is.Birkeland's paper on the aurora, based in part on his brave journey to Northern Norway through 24-hour darkness and temperatures low enough that he nearly died on the trip, marked the first time that anybody (specifically British scientists)

I really hate to nitpick here, since your post was one of the very few intelligentones in this dicussion. However, it is not a surprise to me that you could not find Kristian Birkeland's name mentioned anywhere on the THEMIS web site.Birkeland's story just happens to be interesting enough that someone wrote a popular book about his arctic adventures. I have heard from several scientists that Lucy Jago's book about Birkeland is an interesting read, but that she does not get everything exactly right and the

Your point is very well taken. In researching the publications on this mission, I noticed myself that it was really difficult to understand what was the real purpose of the mission. I remain quite confused.I'm interested in something else that you mentioned...

Some pretty interesting processes that ultimately result in energy being dumped into the Earth' ionosphere during auroral displays start in the magnetotail. Unfortunately, while thinking about things like magnetic reconnection, magnetic field dipola